Still
No Association Between MMR Vaccination and Neurologic Disorders

Question

Is there any association between MMR vaccine
and neurologic disorders such as encephalitis, meningitis, or autism?

Clinical
Bottom Lines

A retrospective study showed no association between MMR vaccination
and neurologic disorders such as encephalitis, meningitis, and autism.1

The study showed a protective effect of the vaccination against encephalitis
and aseptic meningitis.

Summary of Key Evidence

In
the retrospective study, vaccination data on 535,544 children, ages
1-7, vaccinated between November 1982 and June 1986 in Finland were
linked individually with data from a nationwide hospital discharge register
for hospitalizations for encephalitis, aseptic meningitis, and autism.1

Results
showed no significant increase in hospitalizations for encephalitis
or aseptic meningitis within 3 months postvaccination with MMR (p=0.28
and 0.57, respectively).

Results
showed no significant clustering of hospitalizations for autism after
vaccination.

Results
showed a decrease in encephalitis and aseptic meningitis of unspecified
cause in study period suggesting a protective effect of the MMR vaccine.

Additional
Comments

Other studies support findings in this study including study by Fombonne,
et al. in Pediatrics Oct 2001 which showed no evidence for a new variant
of measles-mumps-rubella-induced autism.4

Other neurologic disorders studied include Guillain-Barre syndrome,
which has been shown to not be causally associated with MMR vaccination
in studies.

There have been case studies which have shown clustering of encephalitis
or aseptic meningitis associated with specific strains of MMR vaccines
since withdrawn from use.

There have been no reports of cases of subacute sclerosing panencephalitis
from vaccine strains.